The present invention relates to an apparatus for acquiring a face image using multiple cameras so as to identify a human being located at a remote site, and more particularly to an apparatus for acquiring a face image using multiple cameras, which allows a PTZ camera to track an interest object from among objects detected/tracked by a fixed camera, and obtains an optimum face image for remote human identification from images generated by the PTZ camera.
With the widespread use of closed circuit television (CCTV) cameras, since many limitations occur in monitoring and analyzing to be carried out by a person serving as an administrator and the number of demands for the realtime monitoring function rapidly increases, the demand of an intelligent image monitoring system (also called an intelligent surveillance system) capable of supporting a more efficient image processing method and a more intelligent analyzing method is rapidly increasing.
The typical method for directly monitoring and analyzing images using a person acting as an administrator has a disadvantage in that fatigue of the administrator is increased and his or her concentration is deteriorated as time goes by, such that an intelligent method capable of automatically tracking/analyzing an object from the monitored image is needed.
Therefore, many developers and companies are conducting intensive research into an intelligent video surveillance system to which a video analysis technique (such as detection, classification, and tracking of an object) and biometrics technology are applied, and representative functions of the intelligent video surveillance system correspond to a technique for identifying a person located at a remote site using a camera and a technique for detecting/tracking an object using a camera.
The typical object detection tracking method has been designed to use images acquired by a fixed camera that is capable of capturing a wide-range image at a predetermined magnification. However, a captured image of an interest object (for example, a person or vehicle) within the image received from the fixed camera has very low resolution, so that it is difficult to identify the interest object.
In order to solve the above-mentioned problems, the object detection and tracking technology using on a PTZ camera that is capable of moving in up, down, left, and right directions and can magnify an image at a specific magnification has been widely used. The method for detecting and tracking an object using a PTZ camera is largely classified into a technology for allowing a PTZ camera to independently detect/track an object and a technology for detecting/tracking based on interworking of fixed and PTZ cameras.
The technology for enabling the PTZ camera to independently detect and track the object maps unique/optical information of a general camera to real-world coordinates, such that it can track the object. Generally, the above-mentioned technology zooms in the object to be tracked, controls the camera to be located at the center part of the image and at the same time stores the resultant image, or separates the object (generally, a face image) from the image and stores the separated result.
However, most of the typical object detection/tracking technologies aim to provide higher-definition object information without considering automated remote human identification using object information. In addition, since the object tracking technology controls the camera in such a manner that the interest object is always located at the center part of the image, the image of the interest object may be deteriorated due to excessive number of pan-tilt operations. If the deteriorated image is used as an input signal of the automated remote human identification system, performance or throughput of the system may be greatly deteriorated.
The object detection and tracking technology using a fixed camera and a PTZ camera can enable the PTZ camera to track an interest object using interest region information generated by the fixed camera. In order to interoperate the fixed camera and the PTZ camera, it is necessary for coordinates of an image obtained by the fixed camera to be mapped to physical coordinates of the PTZ camera. However, if installation places of such cameras are changed or if a peripheral environment is changed, a map for coordinates matching between the cameras must be newly updated.
Although the above-mentioned conventional methods have been designed to consider the object detection and tracking technology either using only the PTZ camera or using the fixed and PTZ cameras, it is impossible for the above-mentioned methods to obtain an optimum face image for identification of a human located at a remote site (hereinafter referred to as remote human identification).
The related art of the present invention has been disclosed in Korean Patent Laid-open Publication No. 10-2011-0051308 (published on May 18, 2011), entitled “APPARATUS AND METHOD FOR CAPTURING FACE IMAGE”.